<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>运算符</title>
</head>
<body>
    
</body>
<script>
    let num = "10";
    document.write(num + 5 + "<br>");   // 105
    document.write(num + "5" + "<br>"); // 105
    document.write(num - 5 + "<br>");   // 5
    document.write(num * 5 + "<br>");   // 50  字符串类型数字进行运算，会自动类型转换

    let num2 = 10;
    document.write(num == num2);    // true  == 只比较值是否相同
    document.write(num === num2);   // false === 比较数据类型和值是否相同
</script>
</html>